Steam generators



Deb. 5, 1967 L. J. CULVER 3,356,077

' STEAM GENERATORS 7 Filed April 4, 1966 WYM 2 7 A Home United StatesPatent ABSTRACT OF THE DISCLOSURE A vapor generator for marine useincluding a division wall to form a radiant chamber and a convectionchamber. The convection chamber including two compartments, one of whichhas a reheater therein shielded by a secondary superheater.

In marine installations including a reheater the steam flow through thereheater is not related to the superheated steam output and it may benon-existent when lighting up the boiler or when steaming to supplyauxiliaries in part or when the ship is maneuvering or running astern.The empty reheater must therefore be protected against excessively highgas temperature but must also be located to allow an adequate heat inputto it for reheating the steam to full design duty when required. Also,the reheater surface must be such as to lead to minimum tube metaltemperatures with a limited pressure steam pressure drop as theprovision for reheating is justified only if the total drop between thehigher pressure and the lower pressure turbines is smallgenerally orless of the intermediate pressure.

These objects are achieved in accordance with the inwhich have been usedfor superheatmg in a primary and secondary superheater, the latter beingdisposed so as to screen and reheater and the said passage being one oftwo disposed in parallel between the furnace and the flue and providedwith means for proportioning the relative gas flow through them.

An example of a boiler in accordance with the invention is shown in theaccompanying diagrammatic drawing, in which:

FIGURE 1 is a sectional elevation of the boiler; and

FIGURE 2 is a section taken on the line 2-2 of FIGURE 1.

The boiler has an oil-fired furnace 10 lined with boiler tubes andcontaining a main steam generating tube bank 12 between the usual steamdrum 14 and water drum 16 The combustion gases leave the furnace bypassing beneath a battle wall 18 and through a gap or opening 19 intotwo passages or compartments 20 and 22 separated by an upright baffle orbypass wall 23 (FIGURE 2). The two compartments 20 and 22 lead inparallel to a flue 24 in which is disposed an economiser 26.

Steam from the drum 14 is superheated in a first stage superheater 27which extends across the two compartments 20 and 22 above the lower endof the division wall 18 but below the lower end of the bypass wall 23.

Above the first stage superheater there are in the reheated compartment20 a second stage or secondary superheater 28 and a reheater 30 and inthe heat absorbing compartment 22 a bank of steam or vapor generatingtubes 32. At the upper end of the passage 20 and 22 there are dampers 34and 35, respectively, enabling the relative gas flows through the twopassages to be adjusted at will.

With this arrangement, the reheater is always adequately screened by thesecondary superheater. Also, when it is not required for use, the gasflow past it can be eliminated. It is thus fully protected under allconditions of operation.

The baflle wall 18 and/or the bafie wall 22 can, if desired be formed ofsteam generating tubes, which can be plain or finned, or of plates andcan be used to support the tubular elements in the gas passages.

Further means can be provided for controlling the temperature of thesuperheated steam such as water spray or indirect attemperators or gasby-passes.

The steam generating bank 32 in the gas passage 22 may be supplied withwater by natural circulation but as this involves the provision of alarge number of tubes and a correspondingly large number of piercings ofthe boiler drum-s and therefore a thickening of the drum walls, it ispreferred that the bank be made up of multi-loop tubes supplied from acommon inlet header and discharging either to an outlet header or to aboiler drum. Such tubes can, if desired, be supplied by a circulatingpump so that the circuit resistance can be increased and the number oftubes still further reduced.

The steam generating tubes surrounding the furnace may be arranged fornatural circulation or for forced circulation, in the latter case inconjunction with the steam generating tubes in the by-pass passage 22.

I claim:

1. A vapor generator comprising:

a setting having a furnace chamber therein, said furnace chamber havinga floor;

means for firing said furnace chamber thereby producing combustiongases;

a division Wall vertically located and having a lower end above thefloor of said furnace chamber to form an opening to permit the flow ofcombustion gases under the division wall, said division wall separatingsaid furnace chamber into an inner radiant chamber with said means forfiring and an outer convection chamber;

a primary superheater located in said convection chamber directly abovethe lower end of said division wall;

a bypass wall within said convection chamber and located atsubstantially right angles with said partition wall and also extendingvertically upwardly from said primary superheater, said bypass wallseparating a portion of said convection chamber into a heat absorbingcompartment and reheat compartment;

a secondary superheater located in said reheater compartment;

a reheater located in said reheater compartment above said secondarysuperheater;

heat absorbing means located in said heat absorbing compartment; and

means for controlling the relative flow of gases between said reheatercompartment and said heat absorbing compartment.

2. A vapor generator according to claim 1 wherein said heat absorbingmeans is a bank of vapor generating tubes.

3. A vapor generator according to claim 2 wherein said means forcontrolling the relative flow of gases between said reheater compartmentand said generating compartment is a plurality of dampers at the upperend of said reheater compartment and at the upper end of said heatabsorbing compartment.

4. A vapor generator comprising:

a setting having a furnace chamber therein;

means for firing said furnace chamber thereby producing combustiongases;

a division wall vertically located and having a lower end above thefloor of said furnace chamber to form an opening to permit the flow ofcombustion gases under the division wall, said division Wall separatingsaid furnace chamber into an inner radiant chamber with said means forfiring and an outer convection chamber;

a primary superheater located in said convection chamber directly abovethe lower end of said division wall;

a bypass wall within said convection chamber and located atsubstantially right angles with said partition wall and also extendingvertically upwardly from said primary superheater, said bypass wallseparating a portion of said convection chamber int-o a heat absorbingcompartment and a reheat compartment;

a secondary superheater located in said reheater compartment;

a reheater located in said reheater compartment above said secondarysuperheater;

a bank of vapor generating tubes located in said heat absorbingcompartment;

a plurality of dampers at the upper end of said reheater compartment andat the upper end of said heat absorbing compartment for controlling therelative flow of gases between said reheater compartment and said heatabsorbing compartment; and

an economizer within said convection chamber above said plurality ofdampers above said bypass wall.

References Cited UNITED STATES PATENTS 2,092,299 9/1937 Black et a1.122-480 X 2,628,598 2/1953 Van Brunt 12248() 3,117,560 1/1964 Kuhner122480 X 20 KENNETH W. SPRAGUE, Primary Examiner.

1. A VAPOR GENERATOR COMPRISING: A SETTING HAVING A FURNACE CHAMBERTHEREIN, SAID FURNACE CHAMBER HAVING A FLOOR; MEANS FOR FIRING SAIDFURNACE CHAMBER THEREBY PRODUCING COMBUSTION GASES; A DIVISION WALLVERTICALLY LOCATD AND HAVING A LOWER END ABOVE THE FLOOR OF SAID FURNACECHAMBER TO FORM AN OPENING TO PERMIT THE FLOW OF COMBUSTION GASES UNDERTHE DIVISION WALL, SAID IVISION WALL SEPARATING SAID FURNACE CHAMBERINTO AN INNER RADIANT CHAMBER WITH MEANS FOR FIRE AND AN OUTE CONVECTIONCHAMBER; A PRIMARY SUPERHEATER LOCATED IN SAID CONVECTION CHAMBERDIRECTLY ABOVE THE LOWER END OF SAID DIVISION WALL; A BYPASS WALL WITHINSAID CONVECTION CHAMBER AND LOCATED AT SUBSTANTIALLY RIGHT ANGLES WITHSAID PARTITION WALL AND ALSO EXTENDING VERTICALLY UPWARDLY FROM SAIDPRIMARY SUPERHEATER, AID BYPASS WALL SEPARATING A PORTION OF SAIDCONVECTION CHAMBER INTO A HEAT ABSORBING COMPARTMENT AND REHEATCOMPARTMENT; A SECONDARY SUPERHEATER LOCTED IN SAID REHEATERCOMPARTMENT; A REHEATER LOCATED IN SAID REHEATER COMPARTMENT ABOVE SAIDSECONDARY SUPERHEATER; HEAT ABSORBING MEANS LOCATED IN SAID HEATABSORBING COMPARTMENT; AND MEANS FOR CONTROLLING THE RELATIVE FLOW OFGASES BETWEEN SAID REHEATER COMPARTMENT AND SAID HEAT ABSORBINGCOMPARTMENT.